1. Field of the Invention
The present invention is concerned generally with circuit means for converting AC power to DC power, integrated on a single piece of semiconductor material, and having input terminals for connection to a source of AC power and sufficient additional terminals for connection of several discrete external components necessary for the operation of the circuit.
2. The Prior Art
While it is desirable, from a cost standpoint as well as for other reasons, to provide such a power supply circuit which can be integrated on the same piece of semiconductor material as the circuitry which it drives, such a circuit is not currently available. Portions or sub-blocks of such a circuit, such as diode bridges or other power-supply-oriented diode products, have been assembled and potted into discrete units, and integrated and semi-integrated circuitry has been available for performing voltage and current regulation functions.
The most common of these assemblies is the diode bridge assembly. It consists typically of four discrete P-N diode devices, configured as a full-wave bridge, mounted together with any necessary heat-dissipating members and formed into a rigid structure having four electrical terminals for input and output connections.
The most common integrated circuit power subcircuit is the voltage regulator circuit, having sufficient number of terminals for input and output connections and any necessary external discrete components. Today such circuits are in wide use in the industry.
Among the major shortcomings of the prior art is the failure to incorporate a complete off-line power supply on the same piece of semiconductor material, despite the desirability of such incorporation for the purposes of minimizing cost and assembly time. The provision of such a circuit would enable the integration on a single piece of semiconductor material of both an off-line power supply and the circuitry which it drives.
The integration of rectifier elements on a single piece of semiconductor material has presented technical problems due to the inherent creation of parasitic P-N junction devices which occurs due to the nature of the structure of such elements. The inability to provide such circuits on a single piece of semiconductor material has contributed to increased production costs.